Refer to the Accompanying Table to Answer the Questions

Multiple Choice

Refer to the accompanying table to answer the questions. $$\begin{array} { | l | c | c | } \hline \begin{array} { l } \text { Price of } \\\text { Erasers }\end{array} & \begin{array} { l } \text { Quantity } \\\text { Demanded of } \\\text { Erasers }\end{array} & \begin{array} { l } \text { Quantity } \\\text { Demanded of } \\\text { Pencils }\end{array} \\\hline \$ .50 & 10 & 12 \\\hline \$ 1.00 & 8 & 11 \\\hline \$ 1.50 & 7 & 10 \\\hline \$ 2.00 & 6 & 9 \\\hline \$ 2.50 & 5 & 8 \\\hline\end{array}$$
-The price of erasers increases from $0.50 to $1.00 per eraser. By what percentage does the quantity demanded of pencils change? (Use the midpoint method.)

A) 8.70%
B) 22.22%
C) -22.22%
D) -8.70%
E) 6.67%